Many different types of cutting tools are available for use in a variety of applications. In most industrial situations, either the cutter is rotated or otherwise moved, and the workpiece is maintained stationary. In other situations, the cutter is stationary and the workpiece is rotated or otherwise moved. In yet other applications, both the cutter and the workpiece may be moved at the same time.
Reinstatement cutting machines are special applications where a cutter is utilized for cutting an opening in a plastic liner installed in a deteriorated underground pipe, e.g., a main. The reinstatement cutting machine is moved through the lined main until it is at a location where a lateral pipe connects to the main pipe. The plastic liner previously installed in the main covers the opening to each lateral pipe. The function of the reinstatement cutting machine is to cut a circular opening in the plastic liner where the lateral pipe opens into the main pipe. This operation reinstates the ability of fluids to flow from the lateral pipe into the lined main pipe.
Cutters mounted to reinstatement cutting machines generally rely on three degrees of motion, including a radial motion with regard to the axis of the main pipe, rotational movements in a plane orthogonal to the axis of the main pipe, and axial movements along the axis of the main pipe. Often, the longitudinal movements of the reinstatement cutting machine itself provide one direction of movement of the cutter. The bit of the cutting machine can be mounted to a platform that provides radial movement of the bit toward the sidewall of the liner, as well as rotational movements during the cutting operation. In other types of cutting machines, the platform can be constructed to provide all three types of movements of the bit to accomplish the cutting of a hole in the liner to provide an opening to the lateral. Because the reinstatement cutting machine is moved along the liner of the main, it cannot be directly controlled or observed. Accordingly, remote controls are used to remotely control the various movements of the cutting machine. Video cameras are typically used ahead of the cutting machine to allow the cutting operation to be viewed remotely by the operator of the remote controls.
As can be appreciated, when the reinstatement cutting machine is moved into an underground pipe, the entire mechanism, including the cutter itself, must be very reliable. Otherwise, the entire apparatus must be removed from the pipe, which is not often easy, as a cutter may fail or the mobility of the cutting machine may be lost, while the bit is extended radially into the sidewall opening of the main pipe. The bit mechanism is sometimes destroyed during the forceful removal of the reinstatement cutting machine from the main pipe. In other situations, the reinstatement cutting machine and any associated camera equipment must be removed from the main pipe if the bit of the cutter fails. The bit can fail if it becomes dull, broken or becomes loose from its mounting chuck. As can be appreciated, the more complicated a cutter becomes, the more likely a failure will occur. In addition, the more complicated the design and construction of a cutter, the more costly the device becomes.
From the foregoing, it can be seen that a need exists for cutter apparatus that has fewer parts than prior cutters, is more reliable and is more cost effective. Another need exists for a cutter that provides radial and rotary movements to the cutting bit. Yet another need exists for machine apparatus adapted for efficiently moving a tool in various directions.